CHAPTER 21 High Availability and Performance Strategies for IPsec Site-to-Site VPNs This chapter builds on the preceding chapter (which covered IPsec site-to-site VPN deployment) and explains how you can deploy high availability (HA) between multiple peers and connections. This chapter also covers various quality of service (QoS) meth- ods and their basic deployment for the prioritization of voice traffic traveling through your IPsec site-to-site virtual private network (VPN) tunnel. "Do I Know This Already?" Quiz The "Do I Know This Already?" quiz helps you determine your level of knowledge on this chapter's topics before you begin. Table 21-1 details the major topics discussed in this chapter and their corresponding quiz sections.